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Monday, 10 June 2013

CNC cutting templates are ready

Yet another CAD step, this time fully 2D...
I exported the frame outlines from Inventor and the flat plank templates from Rhino right into AutoCAD that allows simple manipulation of 2D polylines.
I have then drawn the perimeter of the plywood sheet (2.5m x 1.22m) and started fiddling with the shape nesting.
At first I was not too efficient at nesting components but once I got the hang of it I managed to squeeze everything within 10 sheets of play, namely
- eight 9mm for the frames, the transom, all of the planking, the cb case, the rudder stock and blade and other bits and bobs
- two 12mm sheets for the floor and some doublers.

I also manage to save some surface for reusable leftovers.

Here's is how two of the nested sheets look like:

As you can see I elected to cut the frames in one piece only (unlike many other pathfinder builders). I also resorted to "puzzle joints" to join long pieces and align them properly. This applies for instance to the planking and the floor. My concern here was that given that the planking is cut already to the finished size, there is no margin for lining up errors.

The CAD drawings are now with a local company who has also received the Okoume marine ply sheets I bought.
They will cut the templates using their 3mx2m waterjet CNC cutter.... this will take approximately one day at a very reasonable cost...